Poly(N-isopropylacrylamide) (PNIPAM) microgel is a smart polymer that shows a volume phase transition temperature (VPTT) at around 32 °C in aqueous solutions, above which it collapses. In this work, combining experiments and molecular simulations, it is shown that PNIPAM microgels do not always exhibit a collapsed structure above the VPTT. Instead, PNIPAM in aqueous alcohol mixtures shows a two-step conformational transition, i.e., a collapse at low temperatures (T < 32 °C) and a reswelling when T > 50 °C. The present analysis indicates that delicate microscopic interaction details, together with the bulk solution properties, play a key role in dictating the reswelling behavior. Even when PNIPAM microgels swell with increasing T, this is not a standard upper critical solution behavior.

Alloying Pt with highly oxophilic transition metals such as Rh, Ni, or Sn has been a promising strategy to modify the electrocatalytic surface properties of Pt in order to supply active oxygen‐containing species for ethanol electrooxidation. A new, highly active, ternary single‐phased fcc PtRhNi/C nanoparticle electrocatalyst for the electrocatalytic oxidation of ethanol (EOR) is reported and its morphology (XRD and TEM), composition (inductively coupled plasma optical emission spectroscopy), and electrochemical activity are discussed in comparison with the state‐of‐art PtRhSn/C electrocatalyst. The EOR activity of the PtRhNi/C material outperformed the benchmark PtRhSn/C material in acidic and alkaline media, showing high stability, especially in alkaline media. The higher intrinsic EOR activity of the Ni‐containing electrocatalyst lends support to the notion that surface NiOx is an excellent oxygenate‐supplying catalyst component for the oxidation of ethanol.

The present study addresses the multiresponsive behavior of poly(N-isopropylacrylamide) (PNIPAM) microgels adsorbed to interfaces. The microgels react to changes in temperature by shrinking in aqueous solution above their volume phase transition temperature (VPTT). Additionally, they shrink in mixtures of water and ethanol, although both individual liquids are good solvents for PNIPAM. The combination of this so-called cononsolvency effect and the temperature response of adsorbed microgels is studied by atomic force microscopy (AFM). Adsorbed microgels are of special interest because they are compressed considerably compared to those in bulk solution. It is shown that the impact of adsorption on swelling depends on the specific surface details, as well as the sample preparation. Thereby, the microgels are deposited on two different kinds of surfaces: on gold surface and on polycation (PAH) coating which show different interactions with the microgels in terms of electrostatic interaction and wettability. In addition, the microgels were deposited from different solvent mixtures. This influences the microgel structure and thereby the swelling properties. Nanorheology studies by dynamic AFM measurements lead to surprising results which are explained by the fact that not only polymer density but a subtle interaction between polymer and solvent might dominate the rheological properties. This work supports the view that preferential adsorption of ethanol at PNIPAM drives cononsolvency, while the shrinking at T > VPTT is caused by general breaking of hydrogen bonds between solvents and PNIPAM.

Polyelectrolyte/microemulsion complexes (PEMECs) are very versatile hybrid systems, combining high loading capacities of microemulsions with larger-scale structuring induced by polyelectrolytes.

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